1) The aperture is the opening behind the lens that effects light coming into the camera by making the hole that the light can come in smaller or larger. 2) The larger the "f" is in the aperture, the larger the depth of field, making more of the picture in focus, and the lower the "f" is the smaller the depth of field is making less of the image in focus. 3) The aperture effects the exposure by letting more or less light in, which can make the image become over or under exposed.